A variety of devices are known for making Z-axis electrical contacts. By “Z-axis” it is intended to refer to an element which extends transversely to the plane of the surface or surfaces to be contacted. One advantage of Z-axis contacts is that they accommodate for irregularities in one or more surfaces being contacted.
Metallic paste for forming electrical contacts has been known for some time. For example, solder pastes include conductive particles in a flux matrix. However, solder pastes have little ability to provide Z-axis connections because once heated they generally have little or no structural integrity.
In a variety of modern electronic packaging used for integrated circuits and other microelectronic devices, a plurality of contacts on one electrical component may be situated on contacts on another electrical component. In the presence of heat, the contacts on one component may melt or soften sufficiently to connect them to components on the other device. Many of these connections are advantageous because they occur in regions which could be accessed otherwise. For example, surface mount packages and ball grid arrays may use this type of connection.
While these products may use conductive bumps, these bumps generally cannot accommodate for a variety of irregularities which may be encountered by contacts. One problem faced with conventional contacts is that a good electrical connection may be possible between two contacts because a native oxide film has formed over one or more of the contacts which prevents the electrical connection. Another difficulty, described above, is that the contacting surfaces often are irregular so that good physical connection is not always possible.
Thus, there is a continuing need for a Z-axis contact which facilitates connection between surfaces which may be irregular, which improves the connection in a variety of surfaces, and which at least in some cases, facilitates connection between surfaces which may be occluded by a native oxide layer.